Total Ozone Thickness 2009

1. Intercomparison between the ozone measurements of the Microtops II and those
made by the Brewer instrument at the RMI at Uccle and several satellites over the last 8 years.2.
Overplot
of 2009 Uccle and meteoLCD total ozone measurements.(new!)3. 3D
plot of total ozone column for latitude region [45 to 50] from
1964 to 2007 and maps
of all of meteoLCD measurements (from WOUDC)

The total thickness of the (stratospheric) ozone layer is measured at unspecified,
irregular intervals using the handheld
Microtops II sensor manufactured by Solar Light Company
of Philadelphia. This instrument measures the thickness of the ozone layer by computing
the ratios of UVB irradiances measured at three different wavelengths; the water vapour content of the
atmosphere and the AOT (aerosol optical thickness) are also measured by the instrument.
The measurement results are given in DU (Dobson Unit). 100 DU correspond to a total
thickness of 1 mm, if the ozone layer were at a standard atmospheric pressure of 1013.25
[HPa]. Common values are in the 250..350 DU range.

The previous years dobsonyy.html files and the Microtops
measurement files can be found in the data area!

Attention: blue lines correspond to
measurements done using instrument #3012. The data in the table are the
original readings multiplied by the calibration factor 1.02955
(instrument_5375 ~
1.02955*instrument_3012)
. Comparison tests made during May and June 2009.

Starting 15 Sep 2009, Microtops #5375 is back from
calibration at Mauna Loa. Purple data correspond to the new calibrated readings.
There is a big difference between the readings before and after calibration. For
some time, measurements will be made with both Microtops, and a conclusion drawn
thereafter.